Fluids injected into wells in drilling operations have long been referred to as drilling muds. Drilling muds have additives to add density and other additives used to control viscosity and to condition drilled formations. Additionally, special muds are used in well completion activities to clean up and condition formations and well bores. The broad category of fluids containing additives and the fluids emerging from wells containing contaminants will hereinafter be referred to as slurries.
Fluid separators are commonly designed to recover additives for reuse and to separate contaminants for discarding. The separators, therefore, become classifiers of sorts and, ideally, remove unwanted materials and allow needed additives to remain in the recirculated slurry. When additives and contaminents both have to be removed from the slurry to extract the contaminents, it then becomes important to be able to separate the extracted total into useful material to be re-introduced into the slurry from useless materials to be discarded. These processes and materials involved are well known to those skilled in the art.
Conditions in well drilling continually change, and such changes alter the relationship between useful additives and useless contaminants. Hydrocyclones best serve the purpose if they have adjustable parameters to alter the nature of extracting proceses to stay optimum as the make-up of entering slurry changes.
Materials fluidly suspended in slurries exposed to a continuously curved flow path move radially in the flowing slurry body. In the absence of turbulence, the separable components of the slurry will move radially outward if heavier and radially inward if lighter. In time all heavier separable material would be at the radially outward dimension of the curved flow. Given a time limit in the curved flow path, the heaviest particles of a given size will be most radially outward. The finer particles of a given specific gravity, however, will not be as far radially outward, in limited time, as the coarser particles. In complex slurries, then, extracting particular materials becomes a complex matter, and hydrocyclones, or their equivalents, need an ability lending themselves to "fine tuning" by those skilled in the art of slurry processing.
In the presence of turbulance attending a curved flow, some finer materials may not move radially outward in the curved flow time available. It is advantageous, then, to reduce flow turbulence in the curved flow path. One of the greatest sources of disturbing turbulence in a curved flow path is the presence of fluid emerging from the curved flow stream in the area occupied by the incoming fluid stream. There is advantage in removing selected strata from the curved flow path before agitated fluids within the confining chamber are encountered.
It has been found that in a curved flow path, reasonably free of turbulence, stratification of materials entrained takes place rather rapidly. This makes possible simplification of the curved flow path confining structure.
It is therefore an object of this invention to provide apparatus to extract preferred strata from a curved path of flowing slurry before the curved flow is admitted to a receiving enclosure.
It is another object of this invention to provide apparatus to produce a curved flow path of slurry and to skin a strata of preselected thickness from the flow path for direction into a separate flow path.
It is yet another object of this invention to provide apparatus to adjust the thickness of the strata skimmed from a curved flow path of slurry.
It is still another object of this invention to provide an adjustable throttle area to control the velocity of slurry introduced into a curved flow path.
It is yet another object of this invention to provide flow rate controls to regulate the flow from extractor skimmer openings extracting preselected strata from a curved path of flowing slurry.
It is yet another object of this invention to provide a series of skimmer blades to extract a succession of strata from a curved stream of slurry, and to direct each skimmed strata into separate exit channels.
It is still a further object of this invention to provide apparatus to analyze effluent from a slurry separator and to utilize the information derived from the analyzer to control means to skim strata from a moving stream of slurry to regulate the thickness of strata skimmed from the stream.
It is yet a further object of this invention to provide apparatus to analyze effluent from a slurry separator and to utilize the output of the analyzer means to control the velocity of the stream of slurry entering a curved path of a slurry separator.
These and other objects, advantages, and features of this invention will be apparent to those skilled in the art from a consideration of this specification, including the attached drawings and appended claims.